1. Field of the Invention
The present invention relates to a toner cartridge filled with a developer made of toner particles or the like, an adaptor for toner cartridge, a toner cartridge assembly, and an electrophotographic image forming apparatus to which the foregoing components are attached detachably.
2. Description of the Related Art
With an image forming apparatus applied with the electrophotographic method, an electrostatic latent image is formed by irradiating light from an exposing device onto the peripheral surface of a photoconductive drum being rotated according to image information obtained by reading a document or transmitted from another device, and a toner image is formed by supplying toner particles from a developing device onto the peripheral surface of the drum on which the electrostatic latent image is formed, after which the toner image is transferred onto a sheet of paper. The sheet bearing the transferred toner image is subjected to a fixing process by heating in a fixing device and discharged to the outside thereafter. To the image forming apparatus configured as above, a toner cartridge is attached detachably in order to replenish the developing device with a developer (toner particles or a mixture of toner particles and a carrier).
Incidentally, the toner cartridge is a consumable article and is normally stored at the site where the image forming apparatus is installed. A toner cartridge being used is replaced with a new one in store as soon as it becomes empty.
Normally, a stirring mechanism having, for example, a spiral feeder, is internally attached to such a toner cartridge. When the toner cartridge is attached to the image forming apparatus, a drive force of a drive source inside the image forming apparatus is transmitted to the stirring mechanism inside the toner cartridge. The stirring mechanism is thus driven so that a developer inside the toner cartridge is replenished to the developing device with stirring. The toner cartridge as above, however, has an inconvenience that the need to provide the stirring mechanism inside the toner cartridge increases the cost.
In order to eliminate this inconvenience, a toner cartridge described, for example, in Patent Document 1 (referred to as the bottle in JP 6-43755) is formed of a circular tubular body. The toner cartridge formed of the circular tubular body is attached to the image forming apparatus and rotated about the tube center. A spiral rib is provided to bulge on the inner peripheral surface of the circular tubular body along the full length. Accordingly, when the toner cartridge rotates, the developer inside the toner cartridge is guided by the spiral rib while it is loosened and eventually migrates toward the opening, so that it is replenished to the developing device through the opening. According to the toner cartridge of JP 6-43755 configured as above, it is possible to achieve a reduction in cost because there is no need to provide the stirring mechanism inside the toner cartridge.
With the toner cartridge of JP 6-43755, however, in a case where the toner cartridge has been stored, for example, in a vertical posture over a long period, the developer falls down to the bottom (end wall) of the toner cartridge in a vertical posture and the developer at the lower end is hardened to form lumps. In a case where the toner cartridge in a state where lumps are formed therein is attached to the image forming apparatus, even when the toner cartridge is rotated about the tube center, the lumps of the developer are hardly pulverized. This results in a problem that the developer cannot be transported toward the developing device.
Incidentally, in order to eliminate this inconvenience, the user is recommended to hold the toner cartridge in hands and shake the toner cartridge sufficiently before he or she attaches the toner cartridge to the image forming apparatus. The user, however, often forgets such a shaking operation.